The secret to these reusable relief-givers lies within - revolutionary TheraBeads®. Activated by microwave or freezer, the non-toxic pellets provide moist heat or dry cold without chemicals or boiling water. The compresses bring skin temperature into therapeutic range in an average of 40 seconds following application and last for 20 minutes. Use the Facial Compress (R1034) for relief from sinus pressure and headache pain. The Moist Heat Collar (R1086) is especially effective in relaxing muscle "knots" often found in the neck and upper shoulders.